On 04/22/2017 10:22 PM, Hans van Kranenburg wrote: > On 04/22/2017 06:55 PM, Chris Murphy wrote: >> On Sat, Apr 22, 2017 at 10:45 AM, Chris Murph >>> The proper way to do this in Btrfs terms would be to COW all of the >>> changed chunk tree nodes elsewhere, all the unneeded items are >>> removed. New CRCs. And then once that succeeds and is committed to >>> stable media, new supers written to point to the new chunk and dev >>> trees which in turn now only point to one of the already written >>> copies of metadata chunks, without writing out new chunks. >> >> Also probably needs free space cache or tree updated. But the main >> point is that nothing is overwritten in Btrfs. It'd always be COW so >> it's fail safe. > > Free space tree only deals with the virtual address space, so it won't > see any difference. Inb4 while that's true, the offline code cannot keep the free space tree (which I'm using) in sync now, so the current only option for that is still to invalidate the whole thing and re-create it on mount again afterwards. :-| -- Hans van Kranenburg -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
